LambdaHack is described as 'Haskell game engine library for roguelike dungeon crawlers'. There are seven games similar to LambdaHack for a variety of platforms, including Windows, Linux, Mac, Steam and Android. The best alternative is Cataclysm: Dark Days Ahead, which is both free and Open Source. Other LambdaHack like games are Pixel Dungeon (Freemium, Open Source), NetHack (Free, Open Source), Brogue (Free, Open Source) and Tales of Maj'Eyal (ToME) (Free, Open Source).
Cataclysm: Dark Days Ahead is a roguelike set in a post-apocalyptic world. Surviving is difficult: you have been thrown, ill-equipped, into a landscape now riddled with monstrosities of which flesh eating zombies are neither the strangest nor the deadliest.
Pixel Dungeon is a traditional roguelike game with pixel-art graphics and simple interface. Explore the depths of Pixel Dungeon, collect useful items, fight fierce monsters to find Amulet of Yendor (surprise!) - the ultimate artifact of this game world.
UnReal World is a unique combination of roguelike roleplaying game and survival simulation set in the Far North long, long ago. Throughout the years, UnReal World has been praised for its depth, realism, atmosphere and immersion.
Caves of Qud is a science fantasy roguelike epic steeped in retrofuturism, deep simulation, and swathes of sentient plants. Come inhabit an exotic world and chisel through layers of thousand-year-old civilizations.